text: class DefaultStorage:
      store = {}
  
      def save(self, key, value):
          self.store.update({key: value})
  
      def get(self, key, default=None):
          return self.store.get(key, default)
  
      def pop(self, key, default=None):
          return self.store.pop(key, default)
  
      def exist(self, key):
          return key in self.store
  
      def find_sid(self, sid):
          for k, v in self.store.items():
              if v.sid == sid:
                  return k, v
          return None, None
  
      def __len__(self):
          return len(self.store)
  